Year % of total population 1960 18.140284317846803 1961 18.1893868986744 1962 18.262627495419775 1963 18.347638027836584 1964 18.42300788500998 1965 18.505400359777628 1966 18.583716332603146 1967 18.649318305769704 1968 18.71329582290632 1969 18.770657294113064 1970 18.82347592501773 1971 18.881871364433035 1972 18.93833806046244 1973 18.990083928813643 1974 19.018506077078115 1975 19.02000137564305 1976 19.02885614874385 1977 19.053710493517535 1978 19.101591023229027 1979 19.181061703907044 1980 19.2062418857707 1981 19.164835049937228 1982 19.136026363932302 1983 19.12472123248848 1984 19.122889325601243 1985 19.117690560352223 1986 19.110274864061775 1987 19.102331810415425 1988 19.09157251832612 1989 19.260304535925833 1990 19.329191435347717 1991 19.109154182813732 1992 18.897642579215017 1993 18.70307215344827 1994 18.514447198225334 1995 18.328148076791816 1996 18.149343463898322 1997 17.97818878525271 1998 17.81392422201378 1999 17.660089884962485 2000 17.50320317235256 2001 17.407487315922847 2002 17.414049247692205 2003 17.420898772226057 2004 17.41637055604025 2005 17.408027012812944 2006 17.392132351408 2007 17.376106080284178 2008 17.36353214345059 2009 17.347597691229367 2010 17.34394010893775 2011 17.350224289132665 2012 17.463042175275458 2013 17.556510701114174 2014 17.649487131565216 2015 17.7373669972289 2016 17.835957792232605 2017 17.92972104725333 2018 17.99893080337871 2019 18.052272503282882 2020 18.13380492954518 2021 18.248042125292653 2022 18.409189708482216 2023 18.540935687149943